1. Field of Invention
The present invention relates to a positioning device for positioning a spectacle lens drilling jig utilized for processing a non-through-hole from the edge of a spectacle lens toward the inside of the lens.
2. Description of Related Art
Rimless-type spectacles have been attracting attention in recent years due to the advantages of a wider field of vision and lighter weight, and as a new type of this rimless spectacles, a method for forming a non-through-hole from the edge of a spectacle lens toward the inside of the lens, and using this non-through-hole for directly connecting to a spectacle lens, an end-piece or bridge and other such frame members is known (Japanese Patent Laid-open No. H7-230062).
FIG. 16 shows an example of the external appearance of the above-mentioned new type of rimless spectacles.
As shown in this figure, the above-mentioned new type of spectacle lenses connect bridge 21 and end-piece 22 to spectacle lens 1 by inserting a pair of protruding portions 23, 23 integrally formed onto both bridge 21 and end-piece 22 into non-through-holes 11, 11 in the edges of the lens, and affixing same in this inserted state with an adhesive or the like.
This new type rimless spectacles is advantageous in that, in comparison to the heretofore rimless spectacles generally referred to as either two-point or three-piece rimless spectacles, the screws that pass completely through the lens surface in the thickness direction can be eliminated, thus enlarging the effective field of vision, and making the spectacles lighter weight. In addition, this new type rimless spectacles is also advantageous in that when wiping the lenses clean, the lack of protrusions makes wiping easy.
To form non-through-holes 11, 11 in the edge of a spectacle lens 1, a drilling jig 3 like that shown in FIGS. 14 and 15 is utilized (Japanese Patent Laid-open No. H7-230062).
FIGS. 14 and 15 show a method for forming a non-through-hole in the edge of a spectacle lens using a drilling jig.
FIG. 14 shows a state in which drilling jigs 3, 3 are respectively affixed to both edges of spectacle lens 1. Further, FIG. 15 shows an exploded view of one portion thereof.
As shown in this figure, drilling jig 3 is shaped like a small block, and is provided with a pair of through guide holes 3l, 31. An edge of this drilling jig 3 is affixed to a predetermined location on an edge of a spectacle lens using two-sided adhesive tape, and thereafter, a step-type pivot drill 33, which has a hole-depth-regulating step disposed on the shaft portion, is inserted into the above-mentioned through guide holes 31, 31 and non-through-holes 11, 11 are formed.
In accordance therewith, non-through-holes 11, 11 of the same spacing as the spacing of the pins of the protruding portions 23, 23 of the bridge 21 and end-piece 22 sides can be easily drilled without using large, expensive processing equipment, such as, for example, a numerically controlled general-purpose milling machine. Further, since the above-mentioned drilling jig 3 is a small block shape, and moreover, is a small-scale and simply structured member having only a pair of through guide holes 31, 31, it is easy to prepare types of drilling jigs 3 that correspond to the different lens shapes of a spectacle lens 1. In other words, no matter what shape a lens 1 might be, it can be handled easily by simply processing (cutting and forming) one edge of a drilling jig 3 to match the curve of the lens edge.
However, in processing the above-mentioned non-through-holes, it was not easy to accurately position and attach a drilling jig 3 to a predetermined drilling location on a spectacle lens edge.
As one method of doing so, there is a method whereby a chart is used and positioning is done by visual observation. In this method, a edged lens is placed on top of a chart on which a reference line corresponding to the shape thereof has been drawn, and using the reference line on this chart as a criteria, a drilling jig is positioned and attached to a predetermined drilling location on the edge of the lens.
However, with this method, there are cases in which a lens cannot be stably placed on a chart due to the lens shape, and further, due to errors that occur as a result of parallax, a great deal of skill is required to perform this work accurately and with good repeatability.
Another method that can be considered is a method whereby a formed jig for securing lens, which affixes an entire lens by having same fitted therein, is used, and a drilling jig is inserted into a space formed beforehand in a prescribed location in this fixing jig, and is attached to the lens edge.
However, this method requires a formed jig for securing lens, which is large enough to enclose an entire lens, and, in addition, since this formed jig for securing lens cannot be used if the shape of the lens changes even slightly, the problem occurs wherein extremely numerous types of formed jigs for securing lens must be readied. For example, even in a case in which a formed jig for securing lens has the same shape as the curved shape of a drilling part, and the same type drilling jig can be used, if the contour shape of a portion of the lens other than the drilling part thereof differs even slightly, a jig that conforms to the different contour shape thereof must be readied. In this manner, in a method, which uses a formed jig for securing lens, the problem occurs of not being able to handle the varied and diverse preferences of spectacle wearers.
With the foregoing problems in view, it is an object of the present invention to provide a positioning device for positioning a spectacle lens drilling jig, which, by its simple structure and simple operation, makes it possible to position accurately and with good repeatability a drilling jig for processing a non-through-hole from an edge of a spectacle lens toward the inside of the lens for a wide variety of lens shapes.
The invention is a positioning device for positioning a spectacle lens drilling jig, characterized in that it comprises lens holder which holds an edged spectacle lens affixed to a blocking jig, while determining the position in the direction of rotation via the above-mentioned blocking jig; biaxial free moving device which freely moves the above-mentioned lens holder up-down and right-left, respectively, relative to a lens surface in a state in which the position in the direction of rotation is fixed; a jig guide base having a guide surface on which a small block-shaped drilling jig is placed in a freely moving manner in the direction of the surface; a guide stopper, which has a guide wall surface formed as the surface for intersecting with the above-mentioned guide surface, and which comes in contact with and positions the above-mentioned drilling jig, which is guided on the above-mentioned guide surface by this guide wall surface; and feeder which feeds the above-mentioned jig guide base, together with the above-mentioned stopper, in the fore-aft direction relative to the above-mentioned lens surface.
A first preferred feature of the positioning device for positioning a spectacle lens drilling jig is characterized in that it comprises a magnetically clamping device which magnetically clamps to the guide wall surface of the guide stopper on one side of a drilling jig placed on the guide surface of the jig guide base.
A second preferred feature of the positioning device for positioning a spectacle lens drilling jig is characterized in that the guide surface on the jig guide base is inclined in the direction of the lens edge.
A third preferred feature of the positioning device for positioning a spectacle lens drilling jig is characterized in that the guide surface of the jig guide base and guide wall surface of the guide stopper are both formed so as to be symmetrical on the right and left.
A fourth preferred feature of the positioning device for positioning a spectacle lens drilling jig is characterized in that the feeder includes a means capable of reading the numerical value of the feed position of the jig guide base and guide stopper.
As described above, it is possible, via a simple structure and simple operations, to position accurately and with good repeatability a drilling jig for processing a non-through-hole from an edge of a spectacle lens toward the inside of the lens for a wide variety of lens shapes.
In addition thereto, it is possible to make a series of operations, from the edging of a lens blank to a drilling process, more efficient.
In accordance therewith, it is possible to achieve the above-mentioned object.